there's two capacitors on the circuit board that i find interesting and a separate motion sensor that makes the lights and sounds upon disc impact. there's also open solder points on the circuit board for other potential mods but not sure if the current is enough to sustain a few more leds.

idea:
one idea could be adding a switch to change power from button batteries to a usb -meaning you would have to supply your own mini or micro usb socket and probably drop voltage to ~ 4v & current to the toy so that the stay-lit mod would work without worry of burning out. the button batteries would still be useful for portability -hence the power toggle switch. when it's on the display stand, switch back to usb and supply your own power to stay lit.